/*
 *  spreadspace avr utils
 *
 *
 *  Copyright (C) 2014-2018 Christian Pointner <equinox@spreadspace.org>
 *
 *  This file is part of spreadspace avr utils.
 *
 *  spreadspace avr utils is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  any later version.
 *
 *  spreadspace avr utils is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with spreadspace avr utils. If not, see <http://www.gnu.org/licenses/>.
 */

#include <avr/io.h>
#include <stdio.h>

#include "serialio.h"

#ifdef USES_LUFA
#include "LUFA/Drivers/Peripheral/Serial.h"
#else
#define SERIAL_UBBRVAL(Baud)    ((((F_CPU / 16) + (Baud / 2)) / (Baud)) - 1)
#define SERIAL_2X_UBBRVAL(Baud) ((((F_CPU /  8) + (Baud / 2)) / (Baud)) - 1)

static inline void Serial_Init(const uint32_t BaudRate, const uint8_t DoubleSpeed)
{
  UBRR0  = (DoubleSpeed ? SERIAL_2X_UBBRVAL(BaudRate) : SERIAL_UBBRVAL(BaudRate));

  UCSR0C = ((1 << UCSZ01) | (1 << UCSZ00));
  UCSR0A = (DoubleSpeed ? (1 << U2X0) : 0);
  UCSR0B = ((1 << TXEN0)  | (1 << RXEN0));

  DDRD  |= (1 << 1);
  PORTD |= (1 << 0);
}

static inline uint8_t Serial_IsSendReady(void)
{
  return ((UCSR0A & (1 << UDRE0)) ? 1 : 0);
}

static inline void Serial_SendByte(const char DataByte)
{
  while (!(Serial_IsSendReady()));
  UDR0 = DataByte;
}

int Serial_putchar(char DataByte, FILE *Stream)
{
  (void)Stream;

  Serial_SendByte(DataByte);
  return 0;
}

static inline uint8_t Serial_IsCharReceived(void)
{
  return ((UCSR0A & (1 << RXC0)) ? 1 : 0);
}

static inline int16_t Serial_ReceiveByte(void)
{
  if (!(Serial_IsCharReceived()))
    return -1;

  return UDR0;
}

int Serial_getchar(FILE *Stream)
{
  (void)Stream;

  if (!(Serial_IsCharReceived()))
    return _FDEV_EOF;

  return Serial_ReceiveByte();
}

void Serial_CreateStream(FILE* Stream)
{
  *Stream = (FILE)FDEV_SETUP_STREAM(Serial_putchar, Serial_getchar, _FDEV_SETUP_RW);
}
#endif



static FILE serial_stream;

void serialio_init(const uint32_t baudrate, const uint8_t doublespeed)
{
  Serial_Init(baudrate, doublespeed);
  Serial_CreateStream(&serial_stream);
  stdin = stdout = stderr = &serial_stream;
}

void serialio_task(void)
{
}

int16_t serialio_bytes_received(void)
{
  return (int16_t)Serial_IsCharReceived();
}